Departamento de Ingeniería Mecánica y Minera
URI permanente para esta comunidadhttps://hdl.handle.net/10953/41
En esta Comunidad se recogen los documentos generados por el Departamento de Ingeniería Mecánica y Minera y que cumplen los requisitos de Copyright para su difusión en acceso abierto.
Examinar
Examinando Departamento de Ingeniería Mecánica y Minera por Materia "621.4 Motores térmicos (excepto máquinas de vapor)"
Mostrando 1 - 3 de 3
- Resultados por página
- Opciones de ordenación
Ítem Methodology improvements to simulate performance and emissions of engine transient cycles from stationary operating modes: A case study applied to biofuels(Elsevier, 2022-03-15) Cruz-Peragón, Fernando; Torres-Jiménez, Eloísa; Lešnik, Luka; Armas, OctavioIn the present study engine/vehicle responses from a standardized transient test cycle are estimated using 13 stationary operating regimes following a previously developed methodology. The main advantage of the methodology tested is that allows obtaining an estimation of transient parameters in a stationary test bench, which requirements are much less demanding than those of the transient test bench. The objectives are: in one hand, to demonstrate that the methodology correctly estimates engine responses regardless of the fuel tested, as it is proposed in a previous paper and, on the other hand, to improve the methodology and the accuracy of the estimated parameters. The fuels tested are renewable fuels from different raw materials (biodiesel from rapeseed, sunflower, and soybean), and diesel fuel as the reference. Biodiesels were tested neat and blended (30% v/v) with diesel fuel. The engine is a common-rail light-duty one, and the standardized testing procedure used to illustrate the implementation of the methodology is the New European Driving Cycle (NEDC). Two design of experiments (DoE) of 13 runs each were analyzed. One of the DoE tested was proposed for characterizing the NEDC, referred as to CTDoE design, while the other one is a five-level fractional factorial design (FFDoE) that adequately matches the optimality criteria of orthogonality, D-optimal criterion, rotatability, and space-filling. The original methodology was improved by the implementation of a new fitting function that simulates the cold start effect over the engine parameters and by a new definition of the boundary in the [n,M] domain. These improvements showed significantly higher accuracy of the estimated engine parameters obtained, both instantaneous and accumulated, respect to the original methodology. The results obtained based on the application of the FFDoE design support the feasibility of the methodology tested. Engine performance and regulated emissions responses, such as intake air and fuel mass flow rate, thermomechanical exergy rate, exhaust gas residual heat rate, total hydrocarbons (THC), nitrogen oxides (NOx), carbon monoxide (CO) and particulate matter (PM) emissions from a transient test were instantaneously and cumulatively predicted with high accuracy using the engine responses from 13 steady-state operating modes.Ítem The effect of HDPE and LDPE pyrolytic oils on cavitation formation in a common-rail diesel injector(Elsevier, 2022-12-15) Lešnik, Luka; Palomar-Torres, Amalia; Torres-Jiménez, Eloísa; Mata-Montes, Carmen; Volmajer, Julija; Kevorkijan, Luka; Biluš, IgnacijoPlastic production and usage increase every year due to its practicality, adaptability, and low-cost production. The problem with plastic arises when it becomes waste and needs to be treated. Most of the plastic we use is produced from petrochemical material that can be used in resource recovery processes like pyrolysis to produce various materials. One of the pyrolysis process products is pyrolytic oil, whose properties are similar to conventional fuels. Minor differences in fuel properties can influence the injection process, in-nozzle flow condition, spray formation and break-up, the combustion process, etc. The presented paper aims to study the influence of pyrolytic oil‘s properties on cavitation formation in the injection nozzle of a common-rail injector. First, the pyrolytic oils were obtained from waste high- and low-density polyethylene using a pyrolysis reactor. Afterwards, the oils were characterized and implemented in the AVL FIRE computation program for studying their influence on cavitation formation in the injection nozzle hole. The obtained results indicate slight differences in fuel properties that influence cavitation formation and spread in the injection hole, which further influence conditions at the exit of the injection hole. The lower lower viscosity of pyrolytic oils influences lower friction in the fuel nozzle flow. The lower density and viscosity of pyrolytic oils promotes cavitation formation, advance time of it appearance at injection hole exit and influence the shorter presence of cavitation in the needle closing phase.Ítem Why we should invest further in the development of internal combustion engines for road applications(EDP SCIENCES S A, 2020-07-02) Lešnik, Luka; Kegl, Breda; Torres-Jiménez, Eloísa; Cruz-Peragón, FernandoThe majority of on-road vehicles today are powered by internal combustion engines, which are, in most cases, burning petroleum-derived liquid fuels mixed with bio-components. The power to weight ratio of internal combustion engines combined with the high energy content of conventional fuels, which can be refilled easily in matter of minutes, makes them ideal for all kinds of road transportation. Since the introduction of EURO emissions norms, the emissions from the Transport sector in the European Union have undergone significant reduction. There are several alternatives to fossil fuels with similar properties, which can replace their usage in the Transport sector. The main focus of research in recent decades has been on biofuels, which can be produced from several sources. The production of biofuels is usually energy more intensive than production of fossil fuels, but their usage can contribute to emission reduction in the Transport sector. In recent years, a lot of effort was also put into promotion of electric vehicles as zero emissions vehicles. This statement should be reconsidered, since the greenhouse impact of electrical vehicles is not negligible. Conversely, in some cases, an electrical vehicle can have an even higher emission impact than modern vehicles with sophisticated internal combustion engines. This is characteristic for countries where the majority of the electricity is produced in coal power plants. With the decrease of greenhouse gas emissions in the Electricity Production sector, and with the increase of battery capacity, the role of electric vehicles in the Transport sector will probably increase. Despite significant research and financial investments in electric vehicles development, the transport sector in near future will be mostly powered by internal combustion engines and petroleum-derived liquid fuels. The amount of pollution from transport sector will be further regulated with stricter emission norms combined with smaller amount of alternative fuel usage.